import Control.Applicative
import Data.List

main :: IO ()
main = solve <$> map read <$> words <$> getLine >>= print

solve :: [Int] -> Int
solve [n, l] = foldl' f 0 $ takeWhile ((<=l).(* (n-1))) ps
  where f ct p = ct + l - (n-1) * p + 1

ps :: [Int]
ps = 2 : unfoldr f 3
  where f x | isP x = Just (x, x+2)
            | otherwise = f (x+2)

isP :: Int -> Bool
isP x = all ((/=0).(mod x)) . takeWhile ((<=x).(^2)) $ ps